<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <script src="https://ajax.aspnetcdn.com/ajax/jquery/jquery-3.5.1.min.js"></script>
  </head>
  <body>
    <div class="error">
      <span id="count"><b> 5 </b></span>
      <a class="btn btn-warning" href="WOWdemo.html">点击返回</a>
    </div>
    <script type="text/javascript" src="js/jquery.js"></script>
    <script type="text/javascript">
      $(function () {
        var count = 5;
        setInterval(function () {
          count--;
          if (count <= 0) window.location.href = '01.html';
          $('#count').html('<b>' + count + '</b>');
        }, 1000);
      });
    </script>
  </body>
</html>
